Abstract
Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) is a component of the replication complex associated with various cellular proteins. It has been reported that G protein pathway suppressor 2 (GPS2) is a potential NS5A-binding factor, as identified in a yeast two-hybrid screens of human cDNA library using viral proteins as baits [1]. In this study, we demonstrated the interaction between GPS2 and NS5A in mammalian cells by coimmunoprecipitation analysis and found that both exogenously and endogenously expressed GPS2 interacted with NS5A of genotype 1b and 2a. Mutagenesis study demonstrated that Domain I of NS5A and coiled-coil domain of GPS2 are responsible for the interaction. Knockdown of GPS2 in hepatoma cell lines suppressed the replication of HCV RNA, which can be rescued by the expression of an RNAi-resistant GPS2. Furthermore, overexpression of GPS2 enhanced the association of NS5A with a proviral cellular factor, human vesicle-associated membrane protein-associated protein A (VAP-A), while knockdown of GPS2 disrupted interaction between VAP-A and NS5A. Taken together, our results suggest that GPS2 acts as a bridge between NS5A and VAP-A and is required for efficient HCV replication.
Highlights
As a growing public health concern, Hepatitis C virus (HCV) infects about 170 million people worldwide and frequently leads to chronic hepatitis, liver cirrhosis and hepatocellular carcinoma (HCC) [2]
To further demonstrate protein interplay between G protein pathway suppressor 2 (GPS2) and nonstructural protein 5A (NS5A) in a more authentic system, HCV Con1 replicon cells and HCVcc infected Huh7.5.1 cells were immunoprecipitated with anti-NS5A antibody and bound proteins were immunoblotted with anti-GPS2 antibody
These results further suggest that GPS2 interacts with NS5A in cells replicating HCV RNA
Summary
As a growing public health concern, Hepatitis C virus (HCV) infects about 170 million people worldwide and frequently leads to chronic hepatitis, liver cirrhosis and hepatocellular carcinoma (HCC) [2]. While no known enzymatic function has been ascribed to NS5A, it interacts with a wide variety of host cell proteins, such as FK506-binding protein 8 (FKBP8) and vesicle-associated membrane proteinassociated protein A (VAP-A), and exerts a wide range of effects on cellular pathways and processes, including innate immunity, host cell growth and proliferation [11,12,13]. Previous studies have shown that VAP-A binds to HCV NS5A and NS5B proteins and is important for the assembly of the HCV replication complex [13,15]. Another VAP family member, VAP-B has been reported to be involved in HCV replication through interaction with NS5A and NS5B [16]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call